Immersion hydropercussive device

ABSTRACT

An immersion hydropercussive device in which a movable housing is rigidly connected to a percussive mass whose bottom face rigidly mounts a bit, a hollow rod located in the housing, the interior of the rod communicating with an acceleration cavity in the percussive mass and with a source of high-pressure fluid, and a piston mounted on the rod. The piston is capable of moving along the rod between the two stops fastened to the rod, and divides the housing into two cavities. The piston is provided with ports to interconnect these cavities while the percussive mass is being accelerated. In one of the cavities of the housing there is provided a stop which interacts with the end of the piston as soon as the percussive mass has been cocked, and mounted in the other cavity of the housing is a liner capable of inertial movement along the walls of the cavity, with the end surface of the liner interacting with the piston following the percussion of the bit together with its rigidly associated masses (the percussive mass and housing) against the rock.

United States Patent [191 Voitsekhovsky et al.

[ Nov. 19, 1974 IMMERSION HYDROPERCUSSIVE DEVICE [76] Inventors: Bogdan Vyacheslavovich Voitsekhovsky; Faina Fedorovna Voitsekhovskaya; Bogdan Bogdanovich Voitsekhovsky, all of ulitsa Maltseva Kottedzh 2, Novosibirsk, USSR.

[22] Filed: Mar. 12, 1973 [21] App]. No.: 340,035

[30] Foreign Application Priority Data Primary Examiner-Henry C. Sutherland Assistant ExaminerWilliam F. Pate, Ill Attorney, Agent, or FirmHolman & Stern 5 7] ABSTRACT An immersion hydropercussive device in which a movable housing is rigidly connected to a percussive mass whose bottom face rigidly mounts a bit, a hollow rod located in the housing, the interior of the rod communicating with an acceleration cavity in the percussive mass and with a source of high-pressure fluid, and a piston, mounted on the rod. The piston is capable of moving along the rod between the two stops fastened to the rod, and divides the housing into two cavities. The piston is provided with ports to interconnect these cavities while the percussive mass is being accelerated. In one of the cavities of the housing there is provided a stop which interacts with the end of the piston as soon as the percussive mass has been cocked, and mounted in the other cavity of the housing is a liner capable of inertial movement along the walls of the cavity, with the end surface of the liner interacting with the piston following the percussion of the bit together with its rigidly associated masses (the percussive mass and housing) against the rock.

4 Claims, 1 Drawing Figure 1 IMMERSION I-IYDROPERCUSSIVE DEVICE BACKGROUND OF THE INVENTION The invention relates to drilling equipment, and more particularly to immersion hydropercussive devices used for drilling wells in average and high-strength rocks.

PRIOR ART Known in the prior art is an immersion hydropercussive device comprising a movable housing and a percussive mass slidably connected therewith. Located in the housing is a hollow rod whose interior is connected to the source of highly pressurized fluid. A piston is installed on the rod, forming therebetween a cavity communicating with the interior of the rod.

At the moment of utmost acceleration of the fluid, the piston of the known device blocks the ports communicating the interior of the rod with the cavity formed between the rod and the piston. As a result, a hydraulic impact takes place in the acceleration cavity located over the housing, thereby initiating the acceleration of the housing the latter accumulating kinetic energy and transmitting it to the rock, although not directly but via an intermediate collision with another body, which in the present case is the percussive mass, carrying the bit.

At the moment of impact of the end surfaces of the housing and the percussive mass, the housing imparts a movement to the percussive mass, thus bringing about an impact against the rock.

However, when utilizing the power of hydraulic percussion, i.e., the kinetic energy of the fluid whose flow is abruptly blocked, for accelerating the percussive mass, the store of the kinetic energy accumulated in the high-pressure manifold and accessible to be utilized with an account taken of the compressibility of the fluid, is rather insignificant, and there is practically no use in increasing the volume of the acceleration cavity, with the factor of efficient conversion of fluid energy to kinetic energy of the percussion mass being rather small, about per cent. This does not make it possible to obtain high energies of percussion.

In addition in the device of the prior art, a portion of the percussion is spent on the impact between the end surfaces which wear out rapidly with large energies of percussion. All percussive well drilling devices known heretofore have been based on transmitting impact energy to soil by way of an intermediate collisison performed inside the device.

OBJECT AND SUMMARY OF THE INVENTION An object of the invention is to provide an immersion hydropercussive device which makes it possible to develop a large energy of percussion (hundreds of times exceeding that in the existing device) while using the hydrostatic operation of fluid to accelerate the percussive mass and thereby extend many times the service life of the bit.

A further object of the invention is to provide an immersion device having a high efficiency factor, which is the ratio of the kinetic energy of the strikes carrying the bit to the hydrostatic energy of the fluid consumed within one impact cycle.

Still a further object of the invention is to provide an immersion hydropercussive device which makes it posa piston installed on the rod so that a cavity is formed therebetween, with this cavity being connected to the interior of the rod, according to the invention the movable housing is rigidly connected to the percussive mass, the piston, being able to move along the axis of the rod, is installed between the two stops fastened to the rod, dividing the housing into two cavities, the first one facing the percussive mass and the second onc, and is equipped with ports for connecting these cavities while accelerating the percussive mass, the first cavity having a stop which interacts with the end surface of the piston on completing the cocking of the percussive mass, and the second cavity having a-Vco-axially .arranged linercapable of sliding along the walls of the cavity whose end surface following the percussion interacts with the piston.

To reduce the capacity while increasing the power of percussion, it is expedient to install a hydroaccumula tor between the source of the high-pressure fluid and the cavity of the rod.

To soften the impact on collision between the liner end and the piston, it is advisable to provide a damping liner which should be constructed in the form of two coaxially arranged hollow cylinders fastened to each other at the bottom of the housing, with the outer cylinder being a little longer than the inner cylinder.

It is also advisable that the stop fastened to the rod facing the first cavity should be constructed so as to be able to absorb shocks.

In the immersion hydropercussive'device constructed according to the present invention, in order to accelerate the percussive mass, use is made of the hydrostatic operation of the fluid which increases with the increase in the volume of the acceleration cavity, thereby making it possible to obtain a proportional increase in the power of the percussion.

The present device allows for developinga power .of percussion being equal to 10 tm at a high frequency-of percussions reaching 3 percussions per second, and is characterized by a much smaller capacity and a high efficiency of about 50 per cent as compared to the drilling rigs utilized at present.

The large power of percussion developed by the'present immersion hydropercussive device allows for drilling wells even with a heavily blunted working tool fastened to the end of the percussive mass and brought in contact with the rock, thereby increasing considerably the speed of drilling since there is no need to change frequently the working tool which requires the laborconsuming operation of lifting and sinking the drilling string.

BRIEF DESCRIPTION oF Tl-IEDRAWINGS The invention is subsequently illustrated by a specific embodiment and the single FIGURE is a longitudinal cross-section of an immersion hydropercussive device, according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS The immersion hydropercussive device shown in the drawing comprises a housing 1 constructed in the form of a hollow cylinder, and a percussive mass 2 rigidly connected to the housing 1 and representing a massive body, e.g. being fabricated from carbon steel weighing about 1.5 t.

Means (not shown in the drawing) for fixing a bit are provided on the end working surface of the percussive mass 2. Installed in the housing 1 is a hollow rod 3 whose interior 4 is communicated at one side with a hydroaccumulator 5, and at the other side with an acceleration cavity formed in the percussive mass 2. Rigidly fastened to the rod 3 are stops 7 and 8, with a piston 9 being able to move along the axis of the rod 3 installed therebetween. The piston 9 divides the inner space of the housing 1 into two cavities, namely a first cavity 10 located adjacent to the percussive mass 2 and a second cavity 11. A circular cavity 12 communicates with the interior 4 of the rod 3 through ports 13 formed between the piston 9 and the rod 3. Besides, provided in the rod 3 are ports 14 which communicate periodically the interior 4 of the rod 3 with the cavity 11 of the housing 1. Ports 15 are formed in the piston 9 to interconnect the cavities l0 and 11. The shape of the stops 8 is such that while installing the piston 9 thereon, the ports 15 in the piston are closed. Installed in the cavity 10 is a stop constructed in the form of a thrust pipe 16 rigidly connected to the percussive mass 2.

Moreover, the cavity 10 is communicated with the surrounding'medium through channels 17 formed in the percussive mass 2. A liner 18 capable of moving axially is installed in the cavity 11, with the liner 18 being constructed in the form of two axially arranged hollow cylinders 19 and 20 interconnected, for example, by welding at the bottom of the housing 1, with the-outer cylinder 20 being a little longer than the inner cylinder 19. Such a construction of the liner 18 is aimed at damping the on collision impact between the liner l8 and the end surface of the piston 9 due to a longitudinal travelling wave generated in the liner. For the same purpose, the stop 8 is constructed as a damper which may consist of a set of washers having a larger thickness in the central portion than on the periphery.

The working fluid is pumped into the hydroaccumulator 5 by a pumping station (not shown in'the drawing) at a pressure of l00-200 atm.

For the hydroaccumulator 5 use can be made of any known hydroaccumulator in which gas is employed as an elastic element, with the product of the maneuverable volume of the hydroaccumulatorby the working pressure in. the high-pressure manifold exceeding onehalf of the percussion power.

While boring deep wells, a drilling string can be employed as a hydroaccumulator, making use of the elastic properties of waterfand the. walls of the drilling string. I

The immersion hydropercussive device operates in the following manner:

4 In the drawing, the hydropercussive mechanism is shown at the instance of the percussive mass being braked by soil, when the liner 18 has separated from the bottom of the housing 1 and runs inertially towards the piston 9 to press it against the lower stop 8 and thus arrest communication between the cavities l0 and 11.

the rod 3 and therefrom through the port 14 to the cavity 11 of the housing 1. As a result, the pressure of the fluid increases in the cavity 11 entailing the movement of the housing 1 together with the percussive mass 2 upwardly, thereby accomplishing the cocking of the percussive mass 2. At the same time, the fluid contained in the cavity 10 of the housing 1 is released into the well through channels 17 in the percussive mass 2.

With the movement of the housing 1 the thrust pipe 16 rigidly connected to the. percussive mass 2 moves together with the housing 1. The thrust pipe 16 touches the end surface of the piston 9, somewhat displacing it, with the ports 13 and 15 being opened, thereby moving abruptly the piston 9 to the stop 7. The fluid proceeds through the ports 13 to the circular cavity 12, thereby retaining the piston 9 on the stop 7 while accelerating the percussive mass 2 together with the bit rigidly secured thereon. As this takes place, the fluid flows from the cavity 11 through the ports 15 to the cavity 10 equalizing the-pressure in the cavities l0 and 11, and the percussive mass 2 is accelerated downwardly under the effect of its own weight and the pressure of the working fluid in the cavity 6 delivering a percussion on the rock. Following the percussion of the percussive mass 2 on the rock, the liner l8, encountering no obstacles, falls down hitting the end surface of the piston 9 which is thrown to the initial position. Then the cycle is repeated.

The device operates in the inclined or horizontal positions practically in the same way as in the vertical position, except for the cocking of the mass 2 which, in this case, is accomplished by a somewhat lower effort in connection with partial or complete absence of the constituent of the effort from the weight of the mass 2.

What is claimed is:

1. An immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive means, two stops rigidly fastened to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed between said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percusteraction between the end surface of the liner and said piston following the percussion of said percussive mass, and a hydroaccumulator installed between the said source of high-pressure fluid and the interior of the rod.

2. The immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive means, two stops rigidly fastened to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed between said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percussive mass and a second cavity, ports formed in said piston for connecting said first and second cavities while accelerating said percussive mass, other ports in said hollow rod for communicating said second cavity with said cavity of said interior of the rod while cocking said percussive mass, another stop formed in said first cavity for interaction with the end surface of said piston upon completion of cocking said percussive mass, a liner installed co-axially in said second cavity provisioned for moving along the walls of this cavity for interaction between the end surface of the liner and said piston following the percussion of said percussive mass, and a hydroaccumulator being constructed in the form of two co-axially arranged hollow cylinders fasted to each other at the bottom of the said housing, with the outer cylinder being somewhat longer than the inner cylinder.

3. An immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive mass, two stops rigidly. fasted to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed be- .tween said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percussive means and a second cavity, ports formed in said piston for connecting said first and second cavities while accelerating said percussive mass, other ports in said hollow rod for communicating said second cavity with said cavity of said interior of the rod while cocking said per cussive mass, another stop formed in said first cavity for interaction with the end surface of said piston upon completion of cocking said percussive mass, a liner installed co-axially in said second cavity provisioned for moving along the walls of this cavity for interaction between the end surface of the liner and said piston following the percussion of 'said percussive mass, and said stop being fastened to said rod facing said first cavity being intended to dampen shocks.

4. An immersion hydropercussive device comprising a movable housing; a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid; a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cav ity in the percussive mass, a piston mounted on said hollow rod with a provision for movement along the axis of the rod, a circular cavity formed between said piston and said hollow rod, said hollow rod having ports communicating said circular cavity with the interior of said rod, said piston dividing said movable housing into two cavities, a first cavity being located adjacent said percussive mass, and a second cavity, a stop rigidly secured on said hollow rod in said first cavity which restricts the movement of said piston in one direction, a stop rigidly secured on said hollow rod in said second cavity which restricts the movement of said piston in the opposite direction, said piston port communicating said first and second cavity, said stop in said first cavity having a shape such sthat when interacting with said end of said piston, it closes said ports in said piston, furtherports in said hollow rod communicating said second cavity in the interior of said rod, another stop rigidly secured on said movable housing in said first cavity, said another stop having such a shape and disposition that as that housing moves towards said source of high-pressure fluid, such stop engages the end of said piston the movement the cocking movement of said percussive mass is completed, thereby displacing said piston from said first stop in said first cavity, a liner coaxially mounted in said second cavity with a provision for inertial movement along the walls of said cavity, and said liner having an end surface interacting with said piston following the percussion of said percussive 

1. An immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive means, two stops rigidly fastened to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed between said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percussive means and a second cavity, ports formed in said piston for connecting said first and second cavities while accelerating said percussive mass, other ports in said hollow rod for communicating said second cavity with said cavity of said interior of the rod while cocking said percussive mass, another stop formed in said first cavity for interaction with the end surface of said piston upon completion of cocking said percussive mass, a liner installed co-axially in said second cavity provisioned for moving along the walls of this cavity for interaction between the end surface of the liner and said piston following the percussion of said percussive mass, and a hydroaccumulator installed between the said source of high-pressure fluid and the interior of the rod.
 2. The immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive means, two stops rigidly fastened to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed between said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percussive mass and a second cavity, ports formed in said piston for connecting said first and second cavities while accelerating said percussive mass, other ports in said hollow rod for communicating said second cavity with said cavity of said interior of the rod while cocking said percussive mass, another stop formed in said first cavity for interaction with the end surface of said piston upon completion of cocking said percussive mass, a liner installed co-axially in said second cavity provisioned for moving along the walls of this cavity for interaction between the end surface of the liner and said piston following the percussion of said percussive mass, and a hydroaccumulator being constructed in the form of two co-axially arranged hollow cylinders fasted to each other at the bottom of the said housing, with the outer cylinder being somewhat longer than the inner cylinder.
 3. An immersion hydropercussive device comprising a movable housing, a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid, a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive mass, two stops rigidly fasted to the hollow rod, a piston mounted on said hollow rod with a provision for movement along the axis of the latter between the two said stops, a circular cavity formed between said piston and said hollow rod, ports in said hollow rod for communicating said circular cavity with the interior of the rod while accelerating said percussive mass, said piston dividing said movable housing in two cavities, a first cavity located adjacent said percussive means and a second cavity, ports formed in said piston for connecting said first and second cavities while accelerating said percussive mass, other ports in said hollow rod for communicating said second cavity with said cavity of said interior of the rod while cocking said percussive mass, another stop formed in said first cavity for interaction with the end surface of said piston upon completion of cocking said percussive mass, a liner installed co-axially in said second cavity provisioned for moving along the walls of this cavity for interaction between the end surface of the liner and said piston following the percussion of said percussive mass, and said stop being fastened to said rod facing said first cavity being intended to dampen shocks.
 4. An immersion hydropercussive device comprising a movable housing; a percussive mass rigidly connected to said movable housing, a source of high-pressure fluid; a hollow rod located in said movable housing, a cavity in said percussive mass, the interior of said hollow rod at one end communicating with said source of high-pressure fluid, and at the other end with said cavity in the percussive mass, a piston mounted on said hollow rod with a provision for movement along the axis of the rod, a circular cavity formed between said piston and said hollow rod, said hollow rod having ports communicating said circular cavity with the interior of said rod, said piston dividing said movable housing into two cavities, a first cavity being located adjacent said percussive mass, and a second cavity, a stop rigidly secured on said hollow rod in said first cavity which restricts the movement of said piston in one direction, a stop rigidly secured on said hollow rod in said second cavity which restricts the movement of said piston in the opposite direction, said piston port communicating said first and second cavity, said stop in said first cavity having a shape such sthat when interacting With said end of said piston, it closes said ports in said piston, furtherports in said hollow rod communicating said second cavity in the interior of said rod, another stop rigidly secured on said movable housing in said first cavity, said another stop having such a shape and disposition that as that housing moves towards said source of high-pressure fluid, such stop engages the end of said piston the movement the cocking movement of said percussive mass is completed, thereby displacing said piston from said first stop in said first cavity, a liner coaxially mounted in said second cavity with a provision for inertial movement along the walls of said cavity, and said liner having an end surface interacting with said piston following the percussion of said percussive mass. 